FIG. 1 shows such a magnetic recording tape cartridge which comprises a cartridge case 1 composed of a top section 1a and a bottom section 1b, and after inner components are mounted into the bottom section 1b, the top section 1a and the bottom section 1b are integrally assembled together. In general, the top section 1a and the bottom section 1b are fastened together at four corners of the case and the front central portion of the cartridge case 1 by tapping screws. In substitution for the tapping screws, the top section 1a and the bottom section 1b may be connected with each other by an ultrasonic welding method.
When the top section 1a and the bottom section 1b are assembled together by the tapping screws, through-holes are formed in the bottom section 1b at connecting portions P.sub.1, P.sub.2, P.sub.3, P.sub.4 and P.sub.5 while pins having screw receiving holes are formed in the top section 1a at the corresponding portions. At the respective connecting portions P.sub.1 to P.sub.5, the tapping screws are inserted into the receiving holes of the top section 1a through the through-holes of the bottom section 1b, and in a conventional magnetic recording tape cartridge, it has heretofore been troublesome to properly align the top section 1a and the bottom section 1b so that the through-hole and the receiving hole are vertically and coaxially in alignment with each other at each of the connecting portions.
That is, in a conventional magnetic recording tape cartridge, the top section 1a is apt to be connected to the bottom section 1b in a longitudinally or traversely shifted condition or in a horizontally rotated condition, and it takes time to correct such displacement.
Such displacement is caused not only by poor performance of assembling of the cartridge case, but depends on accuracy in forming of the top section 1a and the bottom section 1b. Unbalanced cooling distortion in case of plastic forming of the top section 1a and the bottom section 1b causes serious dimensional errors simultaneously in the longitudinal and traverse directions A and B in FIG. 2. It leads to dimensional changes in the direction C at each of the connecting portions at the four corners resulting in warped positional relationship between the top section 1a and the bottom section 1b in the direction C, and thus alignment in the connecting portions P.sub.2 to P.sub.5 at the corners of the cartridge case is further made difficult. Further, since the ends of the top section 1a and the bottom section 1b tend to be outwardly warped when being formed, the top section 1a and the bottom section 1b are liable to separate from each other at the connecting portions P.sub.2 to P.sub.5.
Such displacement between the top section 1a and the bottom section 1b causes not only inferior or unreliable connection at each of the connecting portions, but further causes vertical warp in various tape guide members such as a fixed guide pin 6, a fixed guide cylinder 5 or a freely rotatable guide roller 7 as shown in the drawings (see FIGS. 3-6). This is because the upper and lower ends of the guide pin 6 and the guide cylinder 5 are engaged with and fixed to the inner surfaces of the top section 1a and the bottom section 1b and the shaft 14 is integrally projected from the bottom section 1b, with the upper end of the shaft 14 being engaged with and fixed to the inner surface of the top section 1a. Such vertical warp of these tape guide members should be completely prevented since it naturally results in instable running of the magnetic recording tape.